prepared CHANGELOG.md for upcoming release 0.6.0

Author: ThomasSteinbach

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.6.0] - 2021-04-06
+
 ### Added
 
 * Added config.yml to .github dir to force using issue templates.
@@ -23,7 +25,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
-* **BREAKING** Renamed all occurences of 'job\w*sequence' to 'sequence'. Mainly this renames
+* **BREAKING** Renamed all occurences of 'job*sequence' to 'sequence'. Mainly this renames
   `gcip.core.job_sequence.JobSequence` to `gcip.core.sequence.Sequence`.
 * Changed behavior how PredefinedVariables is handling environment variables.
   PredefinedVariables knows which environment variables are always present or under certain circumstances,